To satisfy demands for wireless data traffic having increased since commercialization of 4th-Generation (4G) communication systems, efforts have been made to develop improved 5th-Generation (5G) communication systems or pre-5G communication systems. For this reason, the 5G communication system or the pre-5G communication system is also called a beyond-4G-network communication system or a post-Long Term Evolution (LTE) system.
To achieve a high data rate, implementation of the 5G communication system in an ultra-high frequency (mmWave) band (e.g., a 60 GHz band) is under consideration. In the 5G communication system, beamforming, massive multi-input multi-output (MIMO), full dimensional MIMO (FD-MIMO), an array antenna, analog beamforming, and large-scale antenna technologies have been discussed to alleviate a propagation path loss and to increase a propagation distance in the ultra-high frequency band.
For system network improvement, in the 5G communication system, techniques such as an evolved small cell, an advanced small cell, a cloud radio access network (RAN), an ultra-dense network, a device to device (D2D) communication, a wireless backhaul, a moving network, cooperative communication, coordinated multi-points (CoMPs), and interference cancellation have been developed.
In the 5G system, advanced coding modulation (ACM) schemes including hybrid frequency-shift keying (FSK) and quadrature amplitude modulation (QAM) modulation (FQAM) and sliding window superposition coding (SWSC), and advanced access schemes including filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) have been developed.
In Open System Interconnection (OSI) 7 layer or Transmission Control Protocol/Internet Protocol (TCP/IP) 5 layer classification, a transport layer corresponding to Layer 4 may perform two functions.
First, in a multi-hop communication network including Internet, the transport layer adjusts the amount of data injected by a transmission node through the network, based on a state and/or a capability of a reception terminal, which is called a “flow control” function.
Second, the transport layer adjusts the amount of data injected by the transmission node through the network, based on a state and/or a capability of links of the network, which is called a “congestion control” function. The congestion control function guarantees fairness between multiple network flows using the network together.
A representative connection-oriented transport protocol in the transport layer is a TCP.